Anna Faris has developed a distinctive ditzy blond routine that can be an acquired taste. She tones down the naive bimbo routine in What's your Number? and, although it's almost an impossible task, does her best to drive this sluggish, predictable romantic comedy along with her charm and spot-on comedic timing.

Faris is Ally Darling, a kooky, artistic young woman who hasn't quite found her niche or soulmate in life. After reading an article in a woman's magazine, she comes to believe that if she adds one more man to the number she has already slept with, she will be single forever. It's the set-up for a wild goose chase as she tracks down all her ex's in the hope one of them is her true love.

With an overly demanding mother (Blythe Danner) to please, her younger sister's (Ari Graynor) wedding to organise and being newly unemployed, there's a touch of deja vu to this female-driven, and female-written comedy, but it's got nothing on Bridesmaids.

It does have its funny moments as Ally reconnects with her tragic list of ex-boyfriends, and although we've seen plenty of these gags before, Faris tries hard to make them feel fresh. It's a tough job though, and the result feels like a series of gags held together by a weak premise. And anyway, we all know Ally's perfect man, her womanising neighbour Colin (Evans), who helps track down her ex's, is right there under her nose.

Evans and Faris work well together, and plenty of other familiar faces pop up to provide a laugh or two, including E! Channel's Joel McHale, Martin Freeman, Farris's real life husband Chris Platt and Brothers and Sisters' Ed Begley jnr.

Faris is warm and charming; probably the only person who could convince us of Ally's crazy mission. However, What's your Number? remains more a question to pop after a few drinks on a Friday night than a memorable rom-com.